Fabrication of Zn-Sr-doped laser-spinning glass nanofibers with antibacterial properties

A new strategy for synthesizing silver doped mesoporous bioactive glass fibers and their bioactivity, antibacterial activity and drug loading performance

A new strategy for preparing mesoporous metal-doped bioactive glass fibers (MBGFs) was designed, which included electrospinning and sulfonating mesoporous PS fibers, precipitating metal ions and bioactive glass sol-gel precursor into the mesoporous polystyrene (PS) fibers and calcinations. Silver-doped mesoporous BGFs (Ag-MBGFs) with a uniform diameter of 1-2 μm and a specific surface area of 40.22 m² g^-1 were prepared as an example and characterized by SEM, XRD, TG, ICP and FTIR. These Ag-MBGFs showed excellent bioactivity, antibacterial properties and drug loading and release performance due to their special mesoporous and fibrous structure. The concentration of Staphylococcus aureus decreased from 1 × 10⁸ colony-forming units per mL (CFU mL^-1) to 2.5 × 10⁶ CFU mL^-1 in 2 h and then to 2 × 10² CFU mL^-1 in 12 h when the concentration of the Ag-MBGFs reached 16 mg mL^-1. BGFs of different compositions and functions could be prepared by the same strategy in a mesoporous PS fiber template, which could enrich materials for constructing orthopedic implants.

Fabrication of Porous Bone Scaffolds Using Alginate and Bioactive Glass

Porous composite scaffold using an alginate and bioactive glass ICIE16M was synthesized by a simple freeze-drying technique. The scaffold was characterized using compression testing, Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), X-ray microtomography (XMT) and scanning electron microscopy (SEM). The bioactivity of the scaffold was evaluated by its ability to form apatite on its surface in simulated body fluid (SBF). The data collected showed evidence that the novel material produced had an appropriate pore size for osteoconduction, with an average pore size of 110 µm and maximum pore size of 309 µm. Statistical analysis confirmed that the glass filler significantly (P < 0.05) increased the collapse yield of the scaffolds compared with pure alginate scaffolds. The ICIE16M glass had an amorphous structure, favorable for bioactivity.

The facile synthesis and bioactivity of a 3D nanofibrous bioglass scaffold using an amino-modified bacterial cellulose template

Porous bioglass (BG) scaffolds are of great importance in tissue engineering because of their excellent osteogenic properties for bone regeneration. Herein, we reported for the first time the use of amino-modified bacterial cellulose (NBC) as a template to prepare a three-dimensional (3D) nanofibrous BG scaffold by a facile modified sol-gel approach under ultrasonic treatment. The results suggested that the amino groups on the BC template could effectively promote the absorption of the deposited CaO and SiO2 precursors, and the as-obtained BG scaffold showed a 3D interconnected porous network structure consisting of nanofibers with a diameter of about 20 nm. Furthermore, the as-obtained BG scaffold showed very good bioactivity after being immersed in SBF for 7 days. This research provides a facile and efficient way to prepare a nanofibrous BG scaffold with 3D porous structure, which can be used as a promising candidate for biomedical applications.

Biodegradable Scaffolds for Bone Regeneration Combined with Drug-Delivery Systems in Osteomyelitis Therapy

A great deal of research is ongoing in the area of tissue engineering (TE) for bone regeneration. A possible improvement in restoring damaged tissues involves the loading of drugs such as proteins, genes, growth factors, antibiotics, and anti-inflammatory drugs into scaffolds for tissue regeneration. This mini-review is focused on the combination of the local delivery of antibiotic agents with bone regenerative therapy for the treatment of a severe bone infection such as osteomyelitis. The review includes a brief explanation of scaffolds for bone regeneration including scaffolds characteristics and types, a focus on severe bone infections (especially osteomyelitis and its treatment), and a literature review of local antibiotic delivery by the combination of scaffolds and drug-delivery systems. Some examples related to published studies on gentamicin sulfate-loaded drug-delivery systems combined with scaffolds are discussed, and future perspectives are highlighted.

Regenerating bone with bioactive glass scaffolds: A review of in vivo studies in bone defect models

Large bone defects resulting from fractures and disease are a medical concern, being often unable to heal spontaneously by the body's repair mechanisms. Bone tissue engineering (BTE) is a promising approach for treating bone defects through providing a template to guide osseous regeneration. 3D scaffolds with microstructure mimicking host bone are necessary in common BTE strategies. Bioactive glasses (BGs) attract researchers' attention as BTE scaffolds as they are osteoconductive and osteoinductive in certain formulations. In vivo animal models allow understanding and evaluation of materials' performance in the complex physiological environment, being an inevitable step before clinical trials. The aim of this paper is to review for the first time published research investigating the in vivo osseous regenerative capacity of 3D BG scaffolds in bone defect animal models, to better understand and evaluate the progress and future outlook of the use of such scaffolds in BTE. The literature analysis reveals that the regenerative capacity of BG scaffolds depends on several factors; including BG composition, fabrication method, scaffold microstructure and pore characteristics, in addition to scaffold pretreatment and whether or not the scaffolds are loaded with growth factors. In addition, animal species selected, defect size and implantation time affect the scaffold in vivo behavior and outcomes. The review of the literature also makes clear the difficulty encountered to compare different types of bioactive glass scaffolds in their bone forming ability. Even considering such limitations of the current state-of-the-art, results generated from animal bone defect models provide an essential source of information to guide the design of BG scaffolds in future.

STATEMENT OF SIGNIFICANCE

Bioactive glasses are at the centre of increasing research efforts in bone tissue engineering as the number of research groups around the world carrying out research on this type of biomaterials continues to increase. However, there are no previous reviews in literature which specifically cover investigations of the performance of bioactive glass scaffolds in bone defect animal models. This is the topic of the present review, in which we have analysed comprehensively all available literature in the field. The review thus fills a gap in the biomaterials literature providing a broad platform of information for researchers interested in bioactive glasses in general and specifically in the outcomes of in vivo models. Bioactive glass scaffolds of different compositions tested in relevant bone defect models are covered.